Anapistula ataecina, Cardoso, Pedro & Scharff, Nikolaj, 2009

Cardoso, Pedro & Scharff, Nikolaj, 2009, First record of the spider family Symphytognathidae in Europe and description of Anapistula ataecina sp. n. (Araneae), Zootaxa 2246, pp. 45-57 : 47-54

Anapistula ataecina sp. n.

( Figs 2–7 )

Type material. Female holotype from Gruta do Fumo, Sesimbra, Portugal (N38° 26.050 W 009°08.650, 210 m altitude); 23.XII.2007; P. Cardoso leg. ( ZMUC 000012700).

Other material (paratypes): 1 female from same locality; 27.II.2005; P. Cardoso leg. ( ZMUC 000012701). 1 female from same locality; 11.IV.2007; P. Cardoso leg. ( ZMUC 000012702). 1 female from same locality; 19.IV.2007; P. Cardoso leg. ( ZMUC 000012703). 7 females from same locality; 23.XII.2007; P. Cardoso leg. ( ZMUC 000012704). 3 females from Gruta do Coelho, Sesimbra, Portugal (N38° 25.800 W 009°08.200, 120m altitude); 30.IV.2005; P. Cardoso leg. ( ZMUC 000012705). 1 female from Gruta da Utopia, Sesimbra, Portugal (N38° 26.050 W 009°08.850, 180m altitude); 01.VI.2006; P. Cardoso leg. ( ZMUC 000012706). 1 female from Gruta da Furada, Sesimbra, Portugal (N38° 25.700 W 009°10.500, 150m altitude); 13.IV.2007; P. Cardoso leg. ( ZMUC 000012707).

Etymology. The species name is derived from “ Ataecina ” (also spelled “Ataegina”), a subterranean world deity in Lusitanian and Celtiberian mythology, goddess of nature, night, healing, death and rebirth.

Taxonomic justification: The relatively low cephalothorax, the presence of posterior spiracles, the complete lack of a palp, and four eyes in two diads, makes it easy to place the new species in Anapistula . However, it is more difficult to compare our new species to congeneric species, since illustrations in the literature are rather poor and inadequate. Only a few authors have described their species in such details as we do here. Given the somatic and genital details presented in the paper, combined with the habitat and geographic isolation of the specimens found in this Portuguese cave system, we do not hesitate to describe this material as belonging to a new species.

In general, all known species of Anapistula have rather similar female genitalia with paired spermathecae connected by lateral ducts to a median duct ( Fig. 7 ). Females of different species are separated on the 1) shape and size of the spermathecae and the detailed proportion of the ducts; 2) presence or absence of epigynal atrium; 3) body size; 4) separation of posterior lateral eyes; and 5) number and distribution of setae on the cephalothorax.

In order to decide whether our Portuguese specimens of Anapistula represented individuals of a known species or should be described as a new species, we compared the Portuguese specimens with the nineteen known species of Anapistula ( Platnick 2009) .

Some species can be disregarded right away, since they have no eyes (the cave species A. troglobia and A. cuttacutta ) or six eyes ( A. boneti ) and two additional species are only known from males and therefore cannot be compared with Anapistula ataecina sp. n.. These are A. bebuia Rheims & Brescovit, 2003 from a cave and A. guyri Rheims & Brescovit, 2003 from litter, both in Brazil. Both species have males that are larger than the females of Anapistula ataecina sp. n. and since males of all known species of Anapistula are considerably smaller than the females, they are not considered to be same species as A. ataecina sp. n. Similarly, A. aquytabuera Rheims & Brescovit, 2003 , A. pocaruguara Rheims & Brescovit, 2003 and A. ybyquyra Rheims & Brescovit, 2003 from Brazil and A. seychellensis Saaristo, 1996 from the Seychelles all have distinct epigynal atria, not seen in Anapistula ataecina sp. n. In a review of the Australasian Anapistula species, Harvey (1998) described the setal pattern of the cephalothorax of males and females of Australasian species and found an interesting pattern that he used in the descriptions of the species. Males and females have similar patterns within each species. All species had either eight or six setae on the cephalothorax and a pattern with either four setae on the clypeus, two setae adjacent to the eye diads, and two setae on the posterior part of thorax (4-2-2 pattern present in A. troglobia , A. bifurcata Harvey, 1998 and A. jerai Harvey, 1998 ) or with four setae on clypeus, two setae adjacent to eyes, and no setae on thorax (4-2-0 pattern present in A. tonga Harvey, 1998 ). Anapistula ataecina sp. n. have a unique pattern with ten setae on cephalothorax of which six are on clypeus, two adjacent to the eyes and two on the posterior part of thorax. Of the remaining seven species of Anapistula worldwide, A. appendix Tong & Li, 2006 from a cave in China are much larger (0.65 long), have lateral epigynal ducts with lobes not present in A. ataecina sp. n. and eight setae on cephalothorax (4-2-2 pattern). A. ayri Rheims & Brescovit, 2003 from Brazil have spermathecae with small lateral triangular projections and a sinouid posterior border of the epigynal plate, characters that are not present in Anapistula ataecina sp. n.

This leaves five species that are so similar to Anapistula ataecina sp. n. that they require special attention. These are A. caecula from forest litter in Ivory Coast, A. secreta from forest litter in Central America, A. benoiti from forest litter in Zaire, A. ishikawai from forest litter in Japan and A. australia from forest litter in Australia . We examined the type material of A. secreta Gertch, 1941 (the type species for the genus Anapistula ), A.benoiti Forster & Platnick, 1977 and A.caecula Baert & Jocqué, 1993 . Comparisons with borrowed material had to be limited to characters that could be observed without dissections, since many species are only known from the type material. Based on these comparisons, we concluded that the material from Portugal represents a new species. The characters that separate the new species from the five species mentioned above are given in the diagnosis below.

Of the nineteen species of Anapistula described worldwide, fourteen species have only been found in litter of various kind of vegetation, whereas five species have been found in caves only. None of the cave species are morphologically similar to Anapistula ataecina sp. n.

The notch on the fangs of Anapistula ataecina sp. n. ( Fig. 4 D) also seems to be present in Anapistula caecula ( Baert & Jocqué 1993: fig. 2) from West Africa and in Anapistula ybyquyra ( Rheims & Brescovit 2003: fig. 6) from southern Brazil, and could thus be a phylogenetic informative character at some higher level.

As far as we know, the spinnerets of Anapistula have never before been described and illustrated and it is therefore unknown whether the surprising lack of a flagelliform spigot on the PLS of the female is unique to Anapistula ataecina or perhaps common to all species of Anapistula . If so, this would be another potential synapomorphy for the genus. All other species of symphytognathids, where the webs are known, produce orb webs with sticky spirals. The lack of a flagelliform spigot in A. ataecina could be related to the modified web (sheet web) built by these spiders.

Diagnosis. Overall, Anapistula ataecina sp. n. is most similar to A. secreta , A. benoiti , A. caecula , A. australia , and A. ishikawai . It can be distinguished from these species by the following combination of characters: adult females 0.43–0.57 long ( A. benoiti 0.61 long; A. ishikawai 0.65 long; A. secreta 0.50; A. caecula 0.48–0.55; A. australia unpublished), spermathecae globular ( Fig. 7 )(kidney-shaped in A. caecula , fig. 1 in Baert & Jocqué 1993, globular in A. australia , A. secreta , A. ishikawai and A. benoiti ), posterior lateral eyes separated by more than six times their diameter ( Fig. 2 D)(PLE separation three times in A. benoiti and A. secreta , six times in A. ishikawai , and eight times in A. australia ), median duct (md) of epigynum broad, approx. 0.25 times the width of the spermathecae ( A. secreta and A. benoiti 0.08, A. caecula 0.18, A. ishikawai 0.13, A. australia 0.07 (from Harvey, 1998)), and lateral ducts (ld) of epigynum short, approximately 0.4 times the length of the median duct ( A. benoiti 0.25, A. australia and A. secreta 0.60, A. caecula 0.66, and A. ishikawai 1.2). Small pit present on mesal side of ALE ( Fig. 3 A – square box and 3C – arrow) not seen in any other described species of Anapistula with SEM images available.

The ratios described above were constant in all the examined specimens of A. ataecina sp. n. and we assume that they could also be constant in the other species, and thereby provide a valuable diagnostic feature when males are unavailable. The outline of the spermathecae is easily seen even without dissection, and the globular shape and relative lengths of ducts are constant in all specimens. Four specimens were dissected to confirm these observations.

Holotype female description. Total length 0.52 (excl. chelicerae). Cephalothorax 0.23 long, 0.19 wide, 0.21 high. Sternum 0.16 long, 0.17 wide. Abdomen 0.32 long, 0.30 wide, 0.33 high. Cephalothorax, sternum and chelicerae yellowish brown. Legs darker. Abdomen light yellowish brown ( Figs 2 D–F). Carapace with four eyes in two diads ( Figs 2 D, 3A–B). ALE and PLE contiguous, the two groups of eyes separated by approximately 5 times the diameter of ALE and more than six times the diameter of PLE. One long seta inserts on mesal side of PLE’s (seen dorsally; Fig. 3 A – arrow). Small pit (sulcus?) present on mesal side of ALE ( Fig. 3 A – square box and 3C – arrow). Clypeus high, approximately three times the diameter of ALE, provided with six long serrated setae in two groups close to clypeal margin ( Figs 3 A–B). Palp completely absent ( Fig. 3 B – arrow). Posterior part of cephalothorax with two short setae ( Fig. 2 D). Chelicerae with two sharp teeth distally ( Fig. 4 D – arrow t) and a characteristic notch on the basal half of fangs ( Fig. 4 D – arrow n). Legs, sternum and chelicerae clothed with setae and bristles; all patellae with a long strong dorsal distal macroseta. Tarsi almost twice as long as metatarsi ( Table 1). Labium wider than long, fused to sternum ( Fig. 4 B). Endites longer than wide, converging ( Fig. 4 B), with well developed serrula ( Fig. 3 D – arrow). Sternum not invaginated at coxae, broadly truncated posteriorly, separating coxae IV by more than their diameter ( Fig. 4 B). Abdomen globular, slightly longer than wide, overhanging spinnerets, covered with long setae ( Figs 2 D– E, 4A). Posterior spiracle present ( Fig. 4 C – S). More than one spiracle opening can be observed on the ventral side of the abdomen, but these may be connected by an internal groove, as seen in other symphytognathoids.

I II III IV Femur 0.19 0.17 0.14 0.19 Patella 0.10 0.09 0.08 0.09 Tibia 0.14 0.12 0.10 0.15 Metatarsus 0.10 0.09 0.08 0.10 Tarsus 0.16 0.15 0.13 0.16 Total 0.69 0.62 0.53 0.69 Spinnerets ( Figs 5 A–D, 6A–B): ALS with major ampullate spigot and three piriform spigots with reduced bases and tartipores interspersed ( Fig. 5 B). PMS with large postero-median minor ampullate spigot, no nubbin, one antero-median cylindrical spigot and one aciniform spigot ( Fig. 5 C). PLS with two aggregate spigots that share a common base (fused, Figs 5 D, 6A–B), two aciniform spigots and two cylindrical spigots. Basal cylindrical spigot separated from the more apical by a deep fold ( Fig. 5 D). Colulus absent.

Epigynum ( Figs 2 F, 4C, 7): paired globular thick-walled spermathecae connected by lateral ducts to a wide median duct widening even further close to the copulatory opening ( Fig. 7 ). Lateral ducts relatively short, compared to median duct (ratio lateral duct / median duct = 0.4). Median duct relatively wide (ratio width of median duct / width of spermathecae = 0.25). Spermathecae clearly visible on the ventral side of the abdomen on adult females ( Fig. 2 F). Despite several attempts to prepare the internal parts of the epigynum for SEM, we did not succeed and did therefore not observe the fertilization ducts.

Variation. Average body length 0.53 (ranging from 0.43–0.57; n = 13). Our single specimen with 0.43 mm is probably the smallest adult female spider ever recorded.

Distribution. The family Symphytognathidae is widespread in tropical and subtropical areas, with a few species reaching southern USA, southern China and Japan ( Fig. 1 ). It was not known from Europe or even northern Africa. The new species was only found in Sesimbra, inside the limits of the Arrábida Nature Park, about 30 km south of Lisbon, Portugal. It was exclusively found living in four caves: Gruta do Fumo, Gruta da Utopia, Gruta do Coelho and Gruta da Furada. All but the latter belong to the Frade cave system. The single female captured in Gruta da Furada, a cave about 2 km from the others, was the only specimen found during three independent visits to the cave, and therefore probably not representative of a self-supporting population in this cave. All the other caves are connected and less than one km apart, the whole cave system probably covers about 1 km 2. Although it is possible that the area of occupancy extends to other regions, extensive work has been made in about 20 caves nearby, without success. Extensive collecting of spiders was also carried out by António de Barros Machado in caves all over Portugal ( Machado 1941; Machado & Machado 1941) during the 1930s. Being both a biospeleologist and a spider specialist, it is unlikely that such remarkable, albeit minute, species would have been overlooked by Barros Machado in other regions of the country.

Natural history. Adult females were found during most of the year, on all visits to the Frade cave system. Egg sacs were found from December to May, with either two or three eggs loosely embedded in a relatively large surrounding mesh of silk ( Fig. 2 C). Usually there was only a single egg sac in each web, but up to three were found in a single web. All known egg sacs in this family are similar, always with a very low number or even a single egg per eggsac ( Harvey 1998, Griswold & Yan 2003). The egg sacs where always hanging from the web, either at the periphery or in a more central position.

Webs. The web of Anapistula ataecina sp. n. is sheet-like, horizontal, with a number of vertical threads suspending this structure from above ( Fig. 2 B). The spider sits in the middle, on the underside. The precise structure depends much on the crevices, and webs with vertical threads on the underside of the web were also observed, especially when webs were placed on vertical crevices. In any case, sheet-webs seem atypical for the family. Coddington (1986) suggested that symphytognathids spin strictly two-dimensional orb webs. Such webs have been reported for various species of Patu ( Griswold & Yan 2003, Miller et al. 2009), Crassignatha ( Miller et al. 2009) and Coddington (1986) and Griswold et al. (1998: fig. 3c) reported similar webs from an unidentified Anapistula found in Puerto Rico. However, Hickman (1931) reported that the Tasmanian Symphytognatha globosa produced webs consisting of a few irregular horizontal threads and compared them to the webs of theridiids. The sheet-like webs of Anapistula ataecina sp. n. may be an adaptation to the particular microhabitat, where webs are built in small holes and crevices in the limestone walls and formations.

Figures

FIGURE 1. Known worldwide distribution of the family Symphytognathidae by countries or regions (according to Platnick 2009 and with new additions by Miller et al. 2009).

FIGURE 2. Adult female of Anapistula ataecina sp. n.: A) live specimen hanging on a single silk line; B) web; C) egg sac; D) dorsal view; E) lateral view; F) ventral view, with spermathecae clearly visible. Live photos: Pedro Cardoso (2 A – B).

FIGURE 3. SEM images of female Anapistula ataecina sp. n.: A) carapace and chelicerae, frontal view. White square delimits two lateral eyes (for close-up see 3 C), white arrow points to setae mentioned in text; B) carapace and chelicerae, antero-lateral view, arrow points to area on endites where pedipalps would have inserted, if the females had pedipalps; C) close-up of lateral eye, with pit (arrow); D) serrula of endites (arrow). Scale bars: A, B, D) 0.01 mm; C) 0.001 mm.

FIGURE 4. SEM images of Anapistula ataecina sp. n.: A) habitus, lateral view; B) sternum, ventral view; C) abdomen, ventral view (S = Spiracle; Ep = Epigynum); D) chelicerae, with two sharp teeth (arrow – t) and notch (arrow – n). Scale bars: A, B) 0.1 mm; C, D) 0.01 mm.

FIGURE 5. SEM images of spinnerets of Anapistula ataecina sp. n.: A) left spinnerets: ALS—Anterior lateral spinnerets, PMS—Posterior median spinnerets, PLS—Posterior lateral spinnerets; B) ALS: major ampullate spigot (MAP), piriform spigots (PI), tartipores (ta); C) PMS: minor ampullate spigot (mAP), cylindrical spigot (CY), aciniform spigot (AC); D) PLS: cylindrical spigots (CY), aciniform spigots (AC), aggregate spigots (AG). Scale bars: A) 0.01 mm; B – D) 0.001 mm.

FIGURE 6. SEM images of posterior spinnerets of Anapistula ataecina sp. n.: A) PMS and PLS spinnerets: cylindrical spigots (CY), aciniform spigot (AC), aggregate spigots (AG). B) PLS spinneret: aggregate spigots (AG). Scale bars: A) 0.01 mm; B) 0.001 mm.

FIGURE 7. Vulva of Anapistula ataecina sp. n.: Spermatheca (Sp), lateral duct (ld), median duct (md), border between lateral duct and spermatheca (A), point on anterior border of lateral ducts where the two ducts meet (B), border of epigastric furrow (C). Scale bar: 0.02 mm.